Remote Sensing of Landscape Change in Permafrost Regions

Abstract

Amplification of global warming in Arctic and boreal regions is causing significant changes to permafrost‐affected landscapes. The nature and extent of the change is complicated by ecological responses that take place across strong gradients in environmental conditions and disturbance regimes. Emerging remote sensing techniques based on a growing array of satellite and airborne platforms that cover a wide range of spatial and temporal scales increasingly allow robust detection of changes in permafrost landscapes. In this review, we summarise recent developments (2010 − 15) in remote sensing applications to detect and monitor landscape changes involving surface temperatures, snow cover, topography, surface water, vegetation cover and structure, and disturbances from fire and human activities. We then focus on indicators of degrading permafrost, including thermokarst lakes and drained lake basins, thermokarst bogs and fens, thaw slumps and active‐layer detachment slides, thermal erosion gullies, thermokarst pits and troughs, and coastal erosion and flooding. Our review highlights the expanding sensor capabilities, new image processing and multivariate analysis techniques, enhanced public access to data and increasingly long image archives that are facilitating novel insights into the multi‐decadal dynamics of permafrost landscapes. Remote sensing methods that appear especially promising for change detection include: repeat light detection and ranging, interferometric synthetic aperture radar and airborne geophysics for detecting topographic and subsurface changes; temporally dense analyses at high spatial resolution; and multi‐sensor data fusion. Remotely sensed data are also becoming used more frequently as driving parameters in permafrost model and mapping schemes. Copyright © 2016 John Wiley & Sons, Ltd.

Remote sensing evaluation of High Arctic wetland depletion following permafrost disturbance by thermo-erosion gullying processes

“…Satellite remote sensing data have played a prominent role in the observation and interpretation of spatial and temporal land cover changes over large spatial extents in the Arctic (Stow et al 2004;Muster et al 2013;Jorgenson and Grosse 2016;Park et al 2016). As a result, NDVI analyses have been applied increasingly in studies of Arctic ecology for various purposes such as reporting climate-induced plant community composition changes (Rudy et al 2013;Beck et al 2015;Pattison et al 2015), quantifying permafrost degradation (Fraser et al 2011;Belshe et al 2013), determining deglaciation effects on tundra vegetation distribution (Raynolds and Walker 2009), or predicting peaks of above-ground plant biomass .…”

Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska

“…Analysis of thermokarst processes based on surface water extent is sensitive, however, to several confounding factors, including seasonal variation in water levels, interannual variation in precipitation, and topographic effects on water retention (flats vs. slopes) [38,39]. Seasonally, water levels and extent on the North Slope peak after spring snowmelt, draw down in midsummer due to evapotranspiration and thawing of the active-layer, and then usually increase in late summer due to rainfall and reduced evapotranspiration [40][41][42].…”

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“…An increase in the active layer thickness can melt some of the ice at the top of the wedge, leading to deeper troughs (Farquharson et al, ). Rapid degradation of IWs has been observed in recent decades (Farquharson et al, ; Fraser et al, ; Frost et al, ; Jorgenson et al, ; Jorgenson & Grosse, ; Liljedahl et al, ), as IW degradation has been accelerated with climate change. Their widespread distribution in the Arctic means that these systems will generate environmental changes and feedback that will likely increase in significance.…”